This invention relates to multistage transmissions and to processes for shifting multistage transmissions.
In conventional multistage transmissions having an input shaft and an output shaft arranged so that the output shaft is axially parallel to the input shaft and can be connected to the input shaft by a pair of gear wheels, the flow of torque from the drive engine through the transmission to the motor vehicle wheels must be interrupted when shifting into a new gear. The length of this interruption in driving force is determined by the period of time needed to synchronize the transmission gears which are to be engaged after shifting.
European Published Application No. 01 73 117 discloses a process for shifting a multistage transmission in which the driving torque of the engine is transmitted to the motor vehicle wheels through a temporary engageable gear stage during the interruption in driving force that occurs during the process of shifting to a higher gear. The temporary gear engagement takes place simultaneously with the interruption in driving force so that the driving torque of the engine is transferred in sequence first from the lower gear stage to the temporary gear stage and then to the higher gear stage in order to transmit a driving force during the shift-up process.